Underreamer



2 Shaw-Sheet 1 INVENTOR. Ed mi 2222; BY MK ATTORNEYS June 28, 1927- INVENTOR. I fldzo'ard ,72'72256', BY

A v "1 {k A TTORNEYS Patented June 28, 1927.

UNITED "STATES PATENT v OFFICE.

EDWARD TIMES, OF LOS ANGELES, CALIFORNIA, ASSIGNOR 'I'O UNION TOOL COMPANY, F TORRANCE, CALIFORNIA, A CORPORATION OF CALIFORNIA.

UNLERREAMER Application filed August 4, 19.23. Serial No. 655,678.

This invention relates to underreamers of the rotary type and an important object of.

the invention is to provide a construction that will permit of partial collapse of the cutters upon comparatively small upward movement of the underreamer body. The advantage of this will be apparent when it is considered that, in .working in a hole where pinching formations tend to restrict the upward travel of the underreamer, if

collapse of the cutters be not initiated immediately upon upward pull on the underreamer body, stickingor freezing of the underreamer results. I

Underreainers ofthis type of prior construction have been made in two sections, the mandrels and springs being housed in closed chambers each formed in part in each section and the sectional construction being required i'n order to assemble the springs and mandrel and in order to gain access to them in case adjustment is required. An advantage incident to this improved construction is that the underreamer body may be manufactured from a single steel forging, thus producing ,a much stronger and shorter tool than is possible with the sectional construction and eliminating the relatively expen- 'sive taper pin and box joint which is necessary with the sectional construction. When the sectional construction is employed it is diflicult to keep the joint packed tightly.

Inthe oldtype of underreamer, of which this is an improvement, the. nozzle bore is directed vertically downward instead of toward the cutting point of the tool as provided for in this improved underreamer.

Owing to the springs in the old constructions being placed in closed chambers costly drilling and reaming operations, unnecessary with this improved construction, were re uired.

nother advantage of this present invention over the older type is that a special.

tool is not required to control the cutters when pulled down to a definite position for lining up the mandrel pin with the hole provided in the body for its removal.

Another advantage of the present con-- struction over the old is that placing of the spring, mandrel and nuts in open grooves 1n the side ofthe underreamer body exposes them to the flushing action of the liquid,

thus keeping them free from mud so that they will functionproperly.

'A still further advantage of this construction is that-collapse of the cutters can be effected without providing the usual notches reamer. This is accomplished by a downwardly reduced spreading bar or tongue, the collapse being completed within approximately 2 inches of upward travel of the underre mer body. K

The accompanying drawings illustrate the 1 invention Figure 1's a longitudinal view of an underreamer the provisions of thls mvention, the cutters being in collapsed position and: portions of view.

Fig. 2 is a longitudinal view, partly in section, of the underreamer shown in Figure 1, the cutters being shown in their expanded positions and portions of the stem being broken away to contract the view.

Fig. 3 is an enlarged plan section on the plane indicated by the line 33, Figure 1. Fig. 4 is an enlarged bottom end view of Figure 1, the cutters and parts connected thereto being omitted.

Fig. 5 is a perspective view of one of the cutters.

Fig. 6 is an enlarged bottom end view of Figure 1, partly in section on a horizontal plane passing through the safety or stop ms. 1 p Referring to the drawings the body 11 of the underreamer is preferably a single steel forging and is provided in its peripheral face with open longitudinally extending grooves or recesses 12, there'being three in this instance, but it is to be understood that the number may be varied by the manufacturer according to the number of cutters it is desired to provide in the tool, there being as many such grooves as there are cutters.

the stem being broken away to contract the \The upper ends of the grooves 12 expand, as indicated at 121, for accommodating the onstructed in accordance with head of a wrench for turning the spring adjusting nuts to be hereinafter described. The lower ends of the grooves 12 constitute shoulders 13 against which thrust coil springs 14 that surround mandrels 15 projecting from the grooves 12 through holes 16 into cutter pockets 17 provided in the lower end of the body. The mandrels 15 are provided at their upper ends with spring seats 18 and nuts 19 to hold the spring seats in place. The spring seats 18 are provided with laterally projecting flanges 20 slidably fitting in ways 201 in the side walls of the grooves 12.

The lower ends of the mandrels 15 are pivoted by pins 21 to the upper ends of cutters 22 said cutters being provided in their upper ends with slots 23 to receive the lower ends of the mandrels. The inner walls of the cutter pockets 17 extend aslant inwardly and downwardly as indicated at 24 for the cutters to ride upon. This is an important feature of the construction and will be further referred to hereinafter. 22 expand in radial planes of the body from their upper ends downwardly toward their middle portions so that when the cutters are fully seated in the pockets 17, as in Figure "2, they are fully expanded to their operating positions, the cutter faces 25, that cooperate with the pocket faces 24 to cause expansion and contraction of the cutters, being aslant downwardly and outwardly with reference to the longitudinal axes of the cutters.

The outer or riding faces 33 of the cutters are continuous and extend to the upper ends of the cutters; instead of terminating in notches, as is customary, to form shoulders for engagement by the lower end of the easing shoe. By eliminating the notches, the cutters are materially strengthened. When the cutters 22 are collapsed, as in Fig. 1, the

=riding faces 33 and the outer faces 34 below said riding faces are substantially parallel with the longitudinal axis of the body as are also inner faces 35 of the lower portion of the cutters.

The inner faces 35 lie at angles ofless than 180 to the cutter faces 25 so that the cutters will have ample clearance between them when in the collapsed position. This construction makes it possible to employ more than two cutters which is an advantage in a rotary bit because two cutters tend to cause the bit to wobble, whereas three cutters, for example, maintain the bit at the axis of the hole and thus effect a more uniform operation of the bit.

Mounted near the lower end of the body 11 and traversing the pockets 17 transversely are. safety or stop pins 26, said pins being of circular cross section and partly em- I bedded in the pocket walls 2 1 and projecting from said walls. I The pins 26 pass through slots- 27 formed 1n the inner faces of the cutters, this construction being common in The cutters tending aslant downwardl an underreamers to limit downward movement of the cutters with respect to the body when the body is elevated to collapse the cutters. The upper walls 28 of the cutter pockets 17 extend aslant inwardly and upwardly as do the upper ends 29 of the cutters so that when the tool is in operation the pressure of the cutters against the formation being drilled will tend to keep said cutters securely seated in their pockets.

To operate the underreamer described above, it will be connected in the usual manner to the rotary drill stem. The cutters will be moved into collapsed position, as in Fig. 1, and inserted .in the casing and the drill stem will be lowered to bring the cutters into engagement with the formation to be drilled. As the cutters emerge from the casing shoe the cutters will be moved into their expanded positions by the springs 14, as in Figure 2. When it is desired to raise the underreamer or to entirely withdraw it from the hole, the drill stem'w ill be pulled upwardly, thus immediately initiating collapsing movement of the cutters since the cutters will tend to be held by the walls of the hole while the body ascends. Because ofthe slanting walls 24 there can be no binding of the cutters on said walls tending to prevent upward motion of the underreamerbody. This, is quite important for, if the cutters did not immediately start to collapse, there woud be danger of the underreamer sticking or freezing in the hole. Such sticking or freezing would necessitate considerable jarring to loosen the underreamer, a very undesirable operation since it might rupture or bend the drill pipe.

In order to admit the circulating liquid to the underreamer and to discharge the same adjacent to the cutters, the body 11 is provided with an axial duct 30 terminating at its lower end in branch ducts 31 that extend extending from the grooves through the holes, springs in the grooves surrounding the mandrels, nuts on the mandrels to re} tain the springs, and cutters collapsibly mounted in the pockets and pivotally connected with the mandrels, andcooperating means on the mandrels and walls, of the grooves to guide the mandrels.

2. An underreamer comprising a body having no less than three cutter pockets in one end, the inner walls of the ockets exinwardly, cut-tersin the pockets slida 1y engaging the inner slanting walls of the pockets, the cutters' being expanded by upward movement thereof relative to the body and being collapsed by downward movement thereof relative to the body, and yielding means tending' o hold the cutters in their expanded poless than three cutters movably Iriounted in pockets in the body, and. means yieldingly holding the cutters against downward movement relative to the body, the upper end of the cutters'a'nd the upper wall of the pockets being at less than a right angle to the inner walls of the pockets, said body havin means operating to collapse the cutters wEen the body is raised and the cutters are held by the formation, said means including inward- .ly and downwardly slanting walls on the body and the inner faces of the lower portions of the cutters lying at angles of less than 180 to the inner faces of the upper ortion of the cutters and said last inner aces engaging said slanting Walls, the outer faces of the cutters below the riding faces being substantially parallel to the inner faces of said lower portions of the cutters.

4. An underreamer comprising a bod provided in its peripheral face with longitudinally extending open grooves and cutter pockets in one end, there being holes connecting the grooves and pockets cutters in the pockets, mandrels extending from the grooves through the holes and pivotally connected with the cutters, spring seats on the mandrels provided with laterally project ing flanges, there being ways in the side walls of the grooves for the flanges to slide in, and springs on the mandrels between the seats and bottom walls ofthe grooves.

'5. An underreamer comprislng a body provided in its peripheral face with longitudinally extending open grooves and cutter pockets in one end, there being holes connecting the grooves and pockets, cutters in the pockets, mandrels extending from the grooves through the holes and pivotally connected with the cutters, means tendin to draw the mandrels out of the holes, an 00- operating means on the mandrels and walls of the grooves to guide the upper ends of the mandrels in the grooves. Signed at Torrance, California, this 5th day of July, 1923. x

EDWARD TIMBS. 

